Airplane Express Position On-off

Airplane Express Position On-off The most basic use of ordinary thyristors is controlled rectification. The familiar diode rectifier circuit is an uncontrolled rectifier circuit. If the diode is replaced by a thyristor, a controlled rectifier circuit can be constructed. Taking the simplest...

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Airplane Express Position On-off

The most basic use of ordinary thyristors is controlled rectification. The familiar diode rectifier circuit is an uncontrolled rectifier circuit. If the diode is replaced by a thyristor, a controlled rectifier circuit can be constructed. Taking the simplest single-phase half-wave controlled rectifier circuit as an example, during the positive half cycle of the sinusoidal AC voltage U2, if the control pole of the VS does not input the trigger pulse Ug, the VS still cannot be turned on, only when U2 is in the positive half cycle, When the control electrode is applied with the trigger pulse Ug, the thyristor is triggered to conduct. Draw its waveforms (c) and (d), and only when the trigger pulse Ug comes, there is a voltage UL output on the load RL. Ug arrives early, the thyristor turns on early; Ug arrives late, and the thyristor turns on later. By changing the time of the arrival of the trigger pulse Ug on the control electrode, the average value UL of the output voltage on the load can be adjusted. In electrical engineering, the half cycle of the alternating current is often set to 180°, which is called the electrical angle. Thus, in each positive half cycle of U2, the electrical angle experienced from the start of the zero value to the instant of the arrival of the trigger pulse is referred to as the control angle α; the electrical angle at which the thyristor conducts during each positive half cycle is referred to as the conduction angle θ. It is obvious that both α and θ are used to indicate the conduction or blocking range of the thyristor for a half cycle of the forward voltage. Controllable rectification is achieved by changing the control angle α or the conduction angle θ to change the average value UL of the pulsed DC voltage on the load.
1: Low-power plastic two-way thyristor is usually used as an acousto-optic control lighting system. Rated current: IA is less than 2A.
2: Large; medium power plastic and iron-sealed thyristors are commonly used as power-type controllable voltage regulator circuits. Like adjustable voltage output DC power supply and so on.
3: High-power high-frequency thyristors are commonly used in industry; high-frequency melting furnaces, etc.